In the hybrid engine, a hybrid vehicle in which the generator motor is mounted on a flywheel of the engine is already put into practical use in passenger cars and commercial cars such as a bus and a truck. In the hybrid vehicle, a configuration in which the generator motor is mounted in a flywheel housing of the engine is also proposed as PTO (Power Take Off) provided in the engine.
Regardless of the hybrid vehicle, desirably components mounted on the vehicle are assembled into compact structures from the viewpoint of restriction of a vehicle installation space. Particularly, the space restriction in a shaft direction of the engine is extremely strict in the restriction of the vehicle installation space.
On the other hand, when the generator motor is mounted, generally a damper is used, in order that relative rotation accuracy between a rotor and a stator is maintained in the generator motor while an influence of a vibration or a shock is relaxed in an output shaft of the engine, and in order that the influence of the shock on drive of a hydraulic pump is relaxed. When the damper is provided in mounting the generator motor, unfortunately the space in the shaft direction of the engine is inevitably sacrificed.
Therefore, a damper function similar to the damper structure can be exerted by adopting a coupling structure of at least two spline joint sections. Additionally, the adoption of the coupling structure can compactly assemble the generator motor mounted on the output shaft of the engine. The generator motor having the compact configuration can be provided in the shaft direction of the engine to reduce the space in the shaft direction of the engine.
The inventor already proposes the configuration in which the generator motor is provided between the output shaft of the engine and an input shaft of the hydraulic pump using the coupling structure instead of the damper structure (see Patent Document 1).
FIG. 17 is a longitudinal sectional view illustrating the configuration of the generator motor described in Patent Document 1 as a conventional example 1 of the present invention. FIG. 17 is a mirror-reversed image of the drawing of Patent Document 1. As illustrated in FIG. 17, in the hybrid engine, a motor housing MH is fixed between an engine housing EH and a pump housing PH. An output shaft 101 of the engine and an input shaft 102 of the hydraulic pump are connected to each other with a cylindrical connection shaft section 140 interposed therebetween.
The output shaft 101 and the connection shaft section 140 are connected so as to be able to rotate integrally by spline joint of an internal spline 171 and an external spline 141. The internal spline 171 is formed in an inner circumferential surface of a flywheel 170 mounted on an end section of the output shaft 101, and the external spline 141 is formed in an outer circumferential surface on one end side of the connection shaft section 140. The connection shaft section 140 and the input shaft 102 are connected so as to be able to rotate integrally by spline joint of an internal spline 142 and an external spline 102a. The internal spline 142 is formed in an inner circumferential surface in the other end section of the connection shaft section 140, and the external spline 102a is formed in an outer circumferential surface of the input shaft 102.
An external spline 143 is formed in an outer circumferential surface in an intermediate section of the connection shaft section 140. The external spline 143 engages an internal spline 131a, and the spline joint is performed between the external spline 143 and the internal spline 131a. The internal spline 131a is formed in an inner circumferential surface of an annular rotor support section 131 that is of one of components of a motor rotor 130. An outer circumferential surface of the annular rotor yoke 135 mounted on the rotor support section 131 and an inner circumferential surface of the ring stator core 120 fixed to an inner wall surface of the motor housing MH are provided with a predetermined air gap.
A screw hole 140a is made in a axial center in an end face on one end section side of the connection shaft section 140, and a stepped retainer 144 is fitted in a circular recessed section formed in the end face while a spring ring 145 is interposed therebetween. The spring ring 145 and the stepped retainer 144 are fixed to the end face on one end section side of the connection shaft section 140 by screwing and tightening a tightening bolt 146 in the screw hole 140a. At this point, an outer circumferential end edge of the spring ring 145 is fitted in a ring groove section formed in an inner circumferential surface of an internal spline 171 of a flywheel 170, thereby blocking relative movement between the connection shaft section 140 and the flywheel 170.
In the configuration of the generator motor, the output shaft 101 of the engine and the input shaft 102 to which a drive force of the output shaft 101 is transmitted can be connected with the connection shaft section 140 interposed therebetween. In the connection shaft section 140, at least two spline joint points are formed. Additionally, the output shaft 101, the input shaft 102, and the connection shaft section 140 are connected by the coupling structure of the spline joint. Therefore, the transmission of a surface vibration or a core vibration and the shock to the input shaft 102 from the engine side can be relaxed by the coupling structure. The power can efficiently be transmitted from the output shaft 101 to the input shaft 102.
The motor rotor 130 of the generator motor can be mounted on the connection shaft section 140 by the spline joint so as to be able to rotate integrally. Therefore, the transmission of the surface vibration or core vibration and the shock to the motor rotor 130 from the engine side can be relaxed.
The motor rotor 130 of the generator motor is retained by the engine housing EH that is of the fixed housing while a bearing 160 is interposed therebetween, so that relative rotating accuracy can be secured between the rotor yoke 135 and stator 120 of the generator motor. Additionally, the generator motor can efficiently generate an electric power, or the generator motor can efficiently drive as a motor.    Patent Document 1: Japanese Patent Application Laid-Open No. 2007-6554